hermano there are many ways to keep aware of helping individuals not feel so alone.
If a young sister sits there at the meeting reading her kindle during the talk or if a teenager sits in the foyer with his headphones on it is obvious that they are there under some sort of duress and that they probably are very isolated and being pressured in some way. Plus they will be objects of fear and dislike at the KH.
Less obvious are those who don't attend all meetings but one thing we can be sure of and that is that they will be pressured to attend more meetings. They may be feeling guilty and isolated.
But at the end of the day it is hard to know exactly what is going on without prying but my suggestion is to develop the habit of trying to converse with everyone but particularly those who seem isolated and the conversations can be about world affairs, sport, entertainment etc. I would not suggest being committed to deliberately following up on such ones though and suggest rather that one would need to be the kind of person who is open to whatever outcome happens - for example if they become stronger in the truth then so be it. It is their life after all and it is important that they do not feel that they are being pressured in any way. On the other hand if there is an answering spirit within someone then they may not feel so alone even if it is only for that moment in time and of course this may never become known to you. Having been controlled for most of adult life I would never try to control another person but would simply try to be respectful and tolerant whilst encouraging confidence in the world outside the KH.